Another Vornoi problem - creating struts to fit a brep surface

I am trying, as part of another project, to create a voronoi strutwork on an arbitary solid surface. (i.e. not a simple surface). I have read much of the forum material on mapping to surfaces - but breps are represented by multiple surfaces so the discussed techniques are not fully workable.

the attached files include my test gh and a solid file to input. I have been able to map a suitable voronoi latticework onto the brep surface - but then I'm stuck. I cannot offset the curves on the brep and create a useable strut surface that way. I cannot intersect swept pipes with the brep surface to create surface patches that could then be joined.

I need some elegant ideas; I seem to be going down a rabbit hole at the moment where I am doing ever more complex workarounds for the grasshopper capabilities. (A case in point; the rail sweep is not working for me for closed 3D polylines, so I am having to cut them up and sweep and cap the segments. Ugh).

Example input brep

Curves on brep - but no simple offset / trim mechanism

Potential rail defining strut trim - but no way to do so...

Brep / rail intersect - but no way to turn this into a surface...

Programme

Voronoi%20strut%20on%20brep%20test.3dm

Voronoi%20struts%20-%20volume%202.gh